/* JFlex example: part of Java language lexer specification */

import java_cup.runtime.*;

/**
 * This class is a simple example lexer.
 */
%%

%public
%class Lexer
%extends Sym

%unicode

%debug
%line
%column

%cup

%{
  StringBuffer string = new StringBuffer();
  Sym sym;

  private Symbol symbol(int type) {
    return new Symbol(type, yyline, yycolumn);
  }
  private Symbol symbol(int type, Object value) {
    return new Symbol(type, yyline, yycolumn, value);
  }
%}

%eof{
  /* your code goes here */
%eof}

LineTerminator = \r|\n|\r\n
InputCharacter = [^\r\n]
WhiteSpace     = {LineTerminator} | [ \t\f]

EndOfLineComment     = "//" {InputCharacter}* {LineTerminator}

Identifier = [:jletter:] [:jletterdigit:]*

DecIntegerLiteral = 0 | [1-9][0-9]*

%state STRING
%state NESTED_COMMENT

%%

/* keywords */
<YYINITIAL> "class"              { return symbol(sym.CLASS); }
<YYINITIAL> "public"             { return symbol(sym.PUBLIC); }


<YYINITIAL> {
  /* identifiers */ 
  {Identifier}                   { return symbol(sym.IDENTIFIER); }
 
  /* literals */
  {DecIntegerLiteral}            { return symbol(sym.INTEGER_LITERAL); }
  \"                             { string.setLength(0); yybegin(STRING); }

  /* operators */
  "="                            { return symbol(sym.EQ); }

  /* comments */
  {EndOfLineComment}             { /* ignore */ }
  "/*"                           { /* your code goes here */ }
 
  /* whitespace */
  {WhiteSpace}                   { /* ignore */ }
}

<STRING> {
  \"                             { yybegin(YYINITIAL); 
                                   return symbol(sym.STRING_LITERAL, 
                                   string.toString()); }
  [^\n\r\"\\]+                   { string.append( yytext() ); }
  \\t                            { string.append('\t'); }
  \\n                            { string.append('\n'); }

  \\r                            { string.append('\r'); }
  \\\"                           { string.append('\"'); }
  \\                             { string.append('\\'); }
}

/* error fallback */
<YYINITIAL>.|\n                  { throw new Error("Illegal character <"+ yytext()+">"); }